Commit 2f2b9a3a authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32s: Reduce default size of module/execmem area 



book3s/32 platforms have usually more memory than 8xx, but it is still
not worth reserving a full segment (256 Mbytes) for module text.
64Mbytes should be far enough.

Also fix TASK_SIZE when EXECMEM is not selected, and add a build
verification for overlap of module execmem space with user segments.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/c1f6a4e47f177d919561c6e97d31af5564923cf6.1724173828.git.christophe.leroy@csgroup.eu
parent ac9f97ff

arch/powerpc/Kconfig

+4 −3
Original line number Diff line number Diff line
@@ -1269,23 +1269,24 @@ config TASK_SIZE_BOOL 
config TASK_SIZE

	hex "Size of user task space" if TASK_SIZE_BOOL

	default "0x80000000" if PPC_8xx

	default "0xb0000000" if PPC_BOOK3S_32

	default "0xb0000000" if PPC_BOOK3S_32 && EXECMEM

	default "0xc0000000"



config MODULES_SIZE_BOOL

	bool "Set custom size for modules/execmem area"

	depends on EXECMEM && ADVANCED_OPTIONS

	depends on PPC_8xx

	help

	  This option allows you to set the size of kernel virtual address

	  space dedicated for modules/execmem.

	  For the time being it is only for 8xx.

	  For the time being it is only for 8xx and book3s/32. Other

	  platform share it with vmalloc space.



	  Say N here unless you know what you are doing.



config MODULES_SIZE

	int "Size of modules/execmem area (In Mbytes)" if MODULES_SIZE_BOOL

	range 1 256 if EXECMEM

	default 64 if EXECMEM && PPC_BOOK3S_32

	default 32 if EXECMEM && PPC_8xx

	default 0

arch/powerpc/include/asm/book3s/32/pgtable.h

+2 −1
Original line number Diff line number Diff line
@@ -196,7 +196,8 @@ void unmap_kernel_page(unsigned long va); 
#endif



#define MODULES_END	ALIGN_DOWN(PAGE_OFFSET, SZ_256M)

#define MODULES_VADDR	(MODULES_END - SZ_256M)

#define MODULES_SIZE	(CONFIG_MODULES_SIZE * SZ_1M)

#define MODULES_VADDR	(MODULES_END - MODULES_SIZE)



#ifndef __ASSEMBLY__

#include <linux/sched.h>

arch/powerpc/mm/book3s32/mmu.c

+2 −0
Original line number Diff line number Diff line
@@ -223,6 +223,8 @@ int mmu_mark_initmem_nx(void) 


	update_bats();



	BUILD_BUG_ON(ALIGN_DOWN(MODULES_VADDR, SZ_256M) < TASK_SIZE);



	for (i = TASK_SIZE >> 28; i < 16; i++) {

		/* Do not set NX on VM space for modules */

		if (is_module_segment(i << 28))